Piston cooling



Oct. 9, 1951 E, ENDSLEY 2,571,022

PISTON COOLING Filed May 29. 1948 43 3 /5 Z 42 INVENTOR Louis E. ENDSLEY 4 ATTORNEY Patented ct. 9, 1951.

UNITED 7-sriS-:FES ver NT VFFlCE.

- ration -ofilllinois "".Applicatiol Maly 29, 11948,' Serial N0. 29,962

Y-.5-'C1ain1s. (Cl. 123`41.38)

bearing carrier cooperatively formed and assembled to define a body crown or'head chamber and a body skirt chamber, and the provision of chamber lseparating Vbailiemmeans having a multiplicity of ports defined by angularly directed vanes such that the flow of acooling medium be@ tween and in the chambers possesses bothv turbulence and velocity characteristics.

Other objects will appear from the following description relating to a presently preferred form of the invention, illustrated inthe accompanying drawing, wherein:

Fig. 1 is a longitudinal sectional elevation 'through a piston assemblyembodying present improvements;

Fig. 2 is transverse sectional view taken atv'line 2-2 in Fig. 1;

Fig. 3 is an enlarged and fragmentary sectional detail at line 3-3 ofv Fig. 2;' and,

Fig. 4 is taken at line 3 4 of Fig. 3. Inthe drawing,A the piston assembly is characterized by a body I having an integrally 'formed crown Il and skirt I2, a connecting rod bearing carrier I3, 'a connecting rod I4, and a ballie means I 5.

spaced, arcuately Ashaped elements I9 which are y located between the vinner elements I'I-and the skirt Ywall o the body I0 to dene an intermediate annular cavity 2t and an outer annular cavity 2|. The strut elements I9 of the outer series are each connected with the Vskirt by a radially directed boss 22. The varrangement of 'these strut elements, there being shown in Fig. 2 yfour elements in each series, is intended tol provid' spaced 'and 4slotllike openings or ports between the center cavityy I8 `and therintermediate cavity 20, and similar ports betweenY theintermediate cavity 2li and the outer cavity 2l'. .'.fThese ports defined by each series of `strut .elements are M`staggered or out of registry whereby toicreate non-linear flow paths for a cooling mediumf. It is to bgnoted that the outer cavity- 2l extends vcompletely about the `internal. peripheryof the crown II and above thebosselements 22f-con- Vnecting with theouter struts I9.

Thebody IE) is further characterized by fthe provision of axially spaced and relativelyithick- AVenedY skirt wall bands 24 and 25, .the band 24|y being located near the crownend of the body and the band 25 near the bottom open end of the body. These thickened skirt wallbands pro--v vide for the formation of suitable annular grooves in which the usual rings may` be seated. .Additionally the upper band 24 is formed at its inner surface with an annular rib 2t which is maychined to provide a cylindrical and shouldered seating surface 2l for engagement by theaperipheral margin of the baille means I5; (Fig. 3). During the machining of this annularseat 2l, the several struts are also machined acrossv their free ends to bring each thereof into endwise terminationV at a common transverseplane of the body Ill. The lower thickened band 25 is internally formed to provide an axially-directed,

vplain cylindrical surface 2B which is a-bearing for the carrier I3.

...The carrier I3fcomprises an integralmember having a flat upper face 3i), an enlargedfcentral section in which are formed the spaced bearing bosses 3l, and a lower radially projecting `ange 32 having a cylindrical margin 33V for a sliding fit at the plain cylindrical skirt surface 28. The bosses 3l are diametrically spaced to receive therebetween the upper apertured end S of the connecting rod I4. A wrist pin 35, and suitable bushing elements are disposed in and between the carrier bosses 3I and rod end 3a to connect the parts for operation, these parts being clearly indicated in Fig. 1. The carrier is also formed with a plurality (four being provided) of axially directed bosses 36 to receive an equal number o1" threaded studs 3l. Each stud 31 engages in a threaded aperture of the bosses 22 and depends at the lower end of the carrier bosses 36 to receive a securing nut 38, whereby the carrierand -body Iilvmay be firmly secured in assembly, las shown in Fig. 1, without restricting the skirt l2 against longitudinal movement relative to the ilange.vr 32 '5 ofthe carrier I3 dueto-varying thermalacondi- VLtions.

Prior to effecting the above described assembly, the baille means I is positioned over the studs 31 and moved to its seat at the peripheral rib 26 and on the free ends of the struts I'I and I9. This baffle I5 is formed from flat plate or sheet material (Figs. 1 and 2) to have stud apertures 40 and a central enlarged aperture 4I. When in position, the baiile means I5 is securely clamped at its central area between the struts l1 and I9 and the upper flat face 30 of the car- .rier I3. It is also peripherally clamped at four .spaced zones between the lower face of each body Astud boss 22 and the upper face of each carrier .stud boss 36. The spaced peripheral zones of the bale means I5 falling between the stud 'bosses are free above and below of any obstruct- ',ing portions oi the structure, and it is in these zones that there is provided a set of now controlling vanes, each set of vanes having a plurality of flow directing vane elements, shown at 42 in Figs. 1 and 2, and more in detail in Figs. 3 and 4.

In Figs. 3 and 4, the plate I5 is suitable formed by a punching and shearing operation to pro- `vide radial vane elements 42 which are each turned to a suitable angle relative to the longi- .tudinal axis of the piston body, or to the plane of "the means I5, so that the adjacent vanes denne :an angulate port 43 opening at opposite faces of 'the plate means. Thus, fluid flow from one side to the other of the bale will be confined to the `four zones of the multiple vane elements 42, and in each such Zone the angularly directed ports 43 will create high velocity streams along the adjacent wall of the piston skirt I2.

In Fig. 1, the location of the baiile means I5 clearly divides the interior spaces between the body Iii and insert I3 into a head end chamber 45 and a skirt end chamber 46. The supply of cooling fluid may be taken from the usual engine lubrication system (not shown) and the connecting rod I4 has an axial channel 47 acting to direct this fluid into the circumferential channel 43 formed in the wrist pin bore at its end 34 where it may flow under pressure about the wrist pin bushing to a top, radially directed port 49 opening toward the central crown cavity I8 dened by the inner series of struts I1. The central Zone of the insert face 3B is suitably apertured at 5I) to provide, with the central opening 4I in the baffle I5, an upwardly opening cavity' above the top zone of the rod end 34. The cooling medium owing into the crown chamber 45 of this assembly eventually passes through the angulate ports 43 to the skirt chamber 46 and is discharged to the crankcase by way of a port 5I in the bearing flange 32 of the insert I3.

When the piston is operating, the pressurized supply of cooling medium is dashed onto the central zone oi the crown ii in the cavity I3 and flows about the struts and through the several cavities formed in the head chamber 45 to the outer peripheral zones thereof. The inertia forces created due to reciprocatory motion ofthe piston causes the cooling medium to pass through the ports 43 at the vanes 42 to the annular skirt chamber 46 where a portion of the cooling medium may escape through port 5i. A portion of the medium is retained in this skirt chamber 45 and during certain times in the cycle of operation, as the inward piston movement toward the crank end of the cylinder, the medium is caused to flow under inertia forces reversely through the vane ports 43 to the crown chamber 45. This reverse flow occurs at high velocity and is dirested by the pitch of the vanes 42 in a spiral path to create great turbulence in the chamber and an intimate contact at the hottest zones of the crown II so that a maximum transfer of heat results. When the piston moves toward the chamber end of the cylinder, this hot medium is dashed through the vane ports 43 to the skirt chamber 46. This cyclic dashing of the cooling medium between the crown and skirt chambers is superposed on the general trend of flow from the supply port 49 in the top zone of the connecting rod end 34 to the skirt outlet port 5I. The beneficial results are that the fluid medium is retained in the piston sufficiently long to absorb and pick up amaximum of the heat imparted to the crown surfaces II, and the fluid medium is forced to dash in and about the crown chamber 45 in intimate contact with the crown surfaces with a great degree of turbulence, Thus. the cooling medium is enabled to pick up heat at a rate which will maintain the piston crown Il and adjacent surfaces at a temperature well within safe limits to insure long life and improved operation of the piston.

Having now described a preferred form of piston assembly embodying the cooling provision of improved character, it is to be understood that the invention may include other forms which come within the spirit and scope of the claims hereto appended.

What is claimed is:

1. In a piston assembly, the combination of a cylindrical piston body having a crown, a skirt, and strut means extending from the crown in a direction axially of the body, said body skirt having a straight cylindrical surface concentric with the body axis, an insert member formed with a flat upper face and a cylindrical bearing surface remote from the upper face, said insert being positionable in the body with its upper face opposed to said strut means, and having its remote cylindrical surface bearing at said straight cylindrical surface of the skirt to maintain the insert spaced from the crown and skirt and thereby provide crown and skirt chambers, the insert further providing an inlet opening in its upper face for supply of cooling medium to the crown chamber and a port adjacent its remote bearing surface for discharge of the cooling medium, and a baffle means disposed between the strut means and the upper face of the insert and arranged to separate the crown andv skirt chambers, said baiile means having sets of vane elements dening ports for the control of the flow of cooling medium between said chambers during piston operation.

2. The combination as defined by claim l, and in which said vane elements are arranged to cause a high velocity ow of the cooling medium under inertia forces imparted to the cooling medium during piston motion, and in which the vane elements are angularly directed relative to the longitudinal piston aXis to direct the flow of cooling medium angularly into each chamber.

3. The combination in a piston assembly of oil cooled type, of a piston body providing a skirt r and a crown formed with a plurality of depending strut elements, an insert member providing spaced bearing bosses and being formed with a flat face at one end and a radially directed flange at its opposite end, the at face having an opening therethrough and the ange having a port, means securing said insert to said body with its flat face adjacent said strut elements and the radial flange bearing against the skirt with a sliding t to permit relative longitudinal expansion of the skirt, a connecting rod carried by and between the insert bosses and providing ow means for directing a supply of cooling oil through the insert opening and against the central area of the crown, and baflie means secured between the insert face and the crown strut elements to project outwardly and separate the piston body interior into crown and skirt chambers, said bafe means providing vane elements defining ports which open between said chambers, the vane elements being angularly turned and closely spaced to effect the flow of high velocity streams of cooling oil to said chambers during the periodic acceleration and deceleration of the piston, the port in said insert flange serving to permit discharge of the cooling oil flowing into the skirt chamber.

4. In a piston assembly of fluid cooled character, the combination of a piston body having a crown and a skirt, an insert member secured within said body and formed with a bearing for a connecting rod, the body and insert being so spaced apart as to form a crown chamber and an annular skirt chamber through and between which cooling iiuid is adapted to flow, and barile means comprising a separate plate element secured Within said body between said chambers, and providing a plurality of relatively spaced vanes directed at an angle to the plane of the plate element, said vanes forming flow controlling ports opening between said chambers to project the cooling iluid at high velocity therebetween under the influence of the inertia forces set up during piston operation.

5. In a piston assembly of fluid cooled character, the combination of a piston body having a crown and a skirt, an insert member secured within said body in spaced relation to the crown and skirt to form a crown chamber and an annular skirt chamber, and a balile plate positioned between said body and insert member to separate said chambers, said baffle plate being formed with a plurality of sets of vane elements adjacent its periphery, the Vane elements of each set being inclined with respect to the plane of the plate and defining ports therebetween for directing the flow of a cooling fluid between said chambers and for imparting high velocity to the cooling fluid as a result of the inertia forces incident to vpiston operation.

LOUIS E. ENDSLEY.

REFERENCES CITED The following references are of record in the i'lle of this patent:

UNITED STATES PATENTS 

